Newt Gingrich on Wednesday formally endorsed Donald Trump for president and didn't rule out being the presumptive GOP nominee's running mate.
"Let me start by saying...I endorse Donald Trump. I'm going to work very hard for the Republican nominee," the former speaker of the House told Fox News' Sean Hannity on Wednesday night.
Gingrich, who ran for president in 2012, said he didn't get involved in the 2016 presidential race previously because he said John Kasich is "a great friend of mine" and he said "Ted Cruz ran a great campaign."
"I tried to be an objective observer," said Gingrich, who served as speaker of the House from 1995 to 1999.
He also didn't rule out being Trump's vice presidential running mate.
"Well, I would certainly talk about it," he said. "I wouldn't turn it down automatically."
According to Bloomberg News, Trump has discussed selecting Gingrich as his running mate in recent days. Trump told the Associated Press on Tuesday that he had narrowed the list down to five or six people, but said he wouldn't reveal who his final choice is until the Republican National Convention in Cleveland this July.
Gingrich was recently critical of Speaker Paul Ryan, saying that it was a mistake for the Wisconsin Republican to say last week that he wasn't ready yet to support Trump.
Oil billionaire T. Boone Pickens, meanwhile, also said on Wednesday at the SALT Conference in Las Vegas that he was endorsing Trump and supported his Muslim entry ban proposal. He is planning to host a fundraiser for a pro-Trump super PAC next month, according to The Wall Street Journal.
Trump isn't the official nominee yet. According to CBS News' latest count, he has picked up 1,133 delegates, just about 100 delegates away from reaching the threshold of 1,237 needed to reach the nomination.